Oscillating bit mortiser



Jan. 6, 1931.

0. ONSRUD OSCILLATING BIT MORTISER Filed July 22, 1929 3 Sheets-Sheet 1 [Zeus-72W 05cc27' Giza/22d.

Jan. 6, 1931.

O. ONSRUD OSCILLATI NG BIT MORTISER Filed July 22, 1929 s sheet-sneet, 2

Jan. 6, 1931. O QNSRUD 1,787,756

OSCILLATING BIT MORTISER Filed July 22, 1929 3 Sheets-Sheet, 5

3 f/g0672707 056a? azzsfdd.

oscAia ONSRUD, or CHICAGO, ILLINOIS, Assrenon TO ONSBUD MACHINE woRKs, mm. or CHICAGO, rumors, A CORPORATION or ILLINOIS oscILLArINe BIT Moamrsnn Application filed J ly 22,

':- kind for obviating interference ofthe mechanismwith curved pieces of work; to provide improved means for umformly moving work into engagement with a reclprocatmg cutting tool so as to increase the depth of the cut formed by each successive stroke of the tool; and to provide apparatus for auto-- matically clamping pieces of work on a work support table before they are carried into engagement with the cutting tool and for releasing them after they have beenretracted from the tool.

An illustrative embodiment of my inven ,tion is shown in the accompanying drawings, in which: I I s Fig. 1 is a side elevation ofa mortising machine embodying my invention.

Fig. 2 is a fragmentary top plan of the mortising machine. I

Fig. 3 is a fragmentary top plan showing the position of the tool holder carriage of the machinewhen the tool is at one end of it's stroke.

Fig. 4 is a fragmentary side elevation partly in section showing the guiding means of the tool holder carriage. Y

j Fig. 5 is a fragmentary horizontal. section taken on the line 5-5;of Fig.4.

Fig. 6 is a geometrical,diagram for proving that the point of the tool-will traverse a straight line in moving laterally.

In the form shown; my improved ,mortis ing machine includes a: frame or support which has a work supporting bed of the type shown in my copending application Serial No. 380,196, filed July 22, 1929, and a shift- 1929. Serial 1%. 380,197.

able tool-holder carriage on which is mounted a tool holder having a rotary cutting tool. Mechanism is provided on the other end of the support for reciprocating the carriage and the carriage is connected with.

the support by guiding apparatus in the form of links which are positioned and pro portioned to governthe movements of the carriage so as to cause thecutting point of the tool to move laterally in a substantially straight path.

: In the construction-illustrated the sup porting frame f themortising machine includes, an extensionZ on which a work support table or, bed 8 is slidably mounted. Reciprocating mechanism is provided on the extension 2 for moving the bedS forwardly and backwardly with respect to the' cutting tool. This mechanism comprises a pneumatic jack 4 of the type. shown in the said copendingapplication, and a rack and pinion 5 and 6 respectivelywithwhich the jack is connected-by a crank 34:. The bed 3 carries an adjustable stop 6.1 for limiting its forward stroke and a pair of pneumatic work clamps'i', each mounted on an adjustable standard 8 which is secured to the forward edge of the bed.

The pneumatic clamps 7 and jack 4 are connectedby conduits 7 .1 and 8.1 with a common controlvalve 9.1 identical in construc- 'tion to the controlva'lve illustrated in my said copending application which is designed to apply the clamps to a piece of work on the table 3 immediately before the bed is moved for-wardlyand to release the clamps after the rearward stroke of the bed. The valve 9.1 is provided with anoperating pedal 10.1 comprising a counterweight 11.1

Shiftably mounted on the top of the frame 1, is acar'riage inthe form of a'platform 9 which includes a tool holder 10, having a cutting tool orbit 1'1 and anelectric motor 12 for rotating the cutting tool. The platform. is secured against vertical movement relative to the frame l'bycleats 13 and ltand it is pivotally attached to the frame ofthe machine by links 15 and 16 which are located in recesses 17 and 18 respectively formed in thetop of the frame.

' Q 19 and pin 20 and at a distance from the bolt lower wall of the recess 17.. The link 16 extends substantially normal to the length of the carriage 9 and is pivotally mounted at one end on a pin 22 which islocated on the bottom of the carriage in line with the bolt 19 substantiallyequal to the length of the link 15.

. cutting tool 11 in a substantially straight with a The other end of the link 16 is'provided pin 23 which is also journaled in an aperture formed in the frame 1. The movement of theplatt'orm is guided by thelinks 15 and 16 in such a manner asto'retain the path and to incline the toolat diverse angles at opposite ends respectively of the stroke of the tool. r I

Geometric proof that straight line motion is'produced' by the construction described maybe seen in Fig. 6 wherein the line. 9 represents that portion of the carriage'which extends between thepin 22 and the pin 20 and the dottedlines 15 which are one-half the length of line 9 represent the positions of the link 15 when the carriage is at any point outside of the middle ofits stroke.

The line between 19 and 20 in Fig. 6 is equal in length to the line 15- and as the point 20 remains onthenormala triangle is formed having equal angles a and The line 15 is also equalin length to the remaining portion (half) of line 9 and therefore asecond triangle having equal angles m and y is formed. These two isoscelestriangles make up a third trianglethe sum of whose three angles 00, b and (g +a) necessarily equal 180. Therefore: I

. y+a=180 (w+b) =18OFF0p-b.

7 for its equal 00, and (a) for This proves the line which represents the path of the end of line 9 (corresponding to the path ofthe end of the cutting tool), is perpendicular to the line through points 20 and 22 and is accordingly a straight line.

In the construction shown the travel of the pivpt 22 is very slight and practically coincident with the normal to the path of the tool. The cutting tool actuallyextends slightly beyond the pin 20 but this overhang is soslight compared tocits distance from the point 22 that the path of the tool point is also practically a straight line. J r

Themechanism'that oscillates the carriage ismounted on the front end of the frame 1 and comprises an electric motor 24, a train of gears 25, andan eccentric driving member '26 which is connected with the carriage 9 by a connecting rod 27 and a bell-crank 28. The

bell-crank 28 is journaled in a bearing 29 on the side of the frame 1 and has a lower arm rotated by the motor 12 and it is cont-ind ously oscillated by the bell crank 28 which is driven by the motor 2st. 7

As the carriage 9 is oscillated the pin 22 at the front end of the carriage travels approximately on a straight line which passes through the centersof the crank shaft 20 and pin 22. Those portions of the rear end of the carriage which are at a distance from the pin 22 substantially equalto twice the length of the link 15 are moved in a straight line which is perpendicular to the theoretical straight line upon whichthe pin 22 travels. The cutting tool 11 is located approximately at that part of the rear-end of the carriage which moves in a straight path and thus the action of the links 15 and 16 upon the carriage confines the cutting tool to a substantially strai ht course.

These links also position the tool 11 at diverse angles at opposite ends respectively of its stroke. v i

The work to be operated upon is placed upon the bed 3 and positioned under the clamps 7 and when the operating pedal 10.1 is depressed the clamps firmly secure the work on the bed which is subsequently moved towards the tool 11 by the jack 4. The tool 11 bores its way 'into' the work as the bed advances and eachstroke of the tool forms a substantially straight cut in the work. The depth of each out can be pred termined byvarying the rate of oscillation of the tool. The length of the cut may be varied by changing-the relation of the con necting rod 27 .with'res'pec-t to the eccentric driving member 26. The linal depth of the resulting recess may be predetermined by 7 setting the adjustable stop 6.1; The diverse angular positions of the bit at the opposite 5 ends of'its stroke produces undercut extremities on the recess formed which permit convenient squaring up of the ends of the recess.

by a chiseling operation.

. The bed 3 may be retracted'at any time by releasing the pedal 10.1 and allowing it to be moved to its initial position by the counterweight 11.1. Thisaction causesthe'jack 1 to move the bedto rearward position and it subsequently releases the clamps 7.

7 Although but one specii'e en'ibodiment ofth s lnvention has been herein shown and 7 described, it will be understood that various details of the construction shown may be altered or omitted without departing from the spirit'of this invention as defined by the following claims. 5

I claim: I 1. A mortising machine comprising a support, a carriage mounted on said support comprising a tool holder having a cutting tool 7 thereon, mechanism on said support for oscillating said carriage, a pair of links each pivotally attached at one end to said support and at the other end. to said carriage, one of said links extending along the carriage and the other at right angles thereto for retaining said cutting tool in an approximately straight course during oscillation of said carriage, a work support table slidably mounted on said frame, and means for reciprocating said table toward and away from said cutting tool. 7

2. A mortising machine comprising a support, a platform slidably mounted on said support, means on said support for preventing vertical. displacement of said platform relative to said support, a link pivotally secured at one end to said support and at its other end to said platform, means for swinging sald platform relative to sald support,

; a cutting tool on one end of said platform,

means on the other end of said platform for guiding the movements of said platform to.

retain said tool in an approximately straight course, and means for moving work into engagement with said tool while said platform is in motion to produce a substantially straight line out in said work.

3. A mortising machine comprising a support, a carriage shiftably and pivotally mounted at one end on said support, a tool holder on the other end of said support having a cutting tool, means for oscillating said carriage, and a link pivotally attached at one end to the center of said carriage and journailed at its other end on said support substantially at the middle position of the cutting end of said tool for guiding the movements of the cutting end of said tool along an approximate tangent to the are through which said carriage oscillates.

it. [it inortising machine comprising a support, a carriage imunted on said support comprising a tool holder and a motor for rotating said tool holder, mechanism on said support :l'or oscillating said carriage, and apair of links each pivoted at one end to said support 7 and at the other end to said carriage, said links being spaced apart longitudinally of the carriage and extending at an angle to each other.

' Signed at Chicago this 18th day of July, 1929.

, OSCAR ONSRUD, 

